Search for a spin supersolid in the novel triangular lattice antiferromagnet ErTa7O19

Ising triangular lattice antiferromagnets represent a promising avenue in the search for enigmatic quantum states of matter. Our previous studies have demonstrated that erbium heptatantalate, ErTa7O19, is a realization of such a system with intriguing magnetic properties. Recent single-crystal neutron diffraction measurements performed on the WISH instrument (RB2320281) have revealed long range magnetic order below TN = 105 mK that seems to coexist with diffuse magnetic scattering, characteristic of exotic disordered quantum states. Here we propose additional high-statistics measurements on the WISH instrument in the (HK0) scattering plane to determine the nature of this diffuse signal, as well as additional measurement in the (HHL) scattering plane to determine the size of both the out-of-plane and the in-plane components of the ordered magnetic moment. This should allow us to confirm whether the highly-sought-after spin supersolid state is present in ErTa7O19.